Because of the widespread role of zinc in several bodily functions, the symptoms of zinc deficiency can arise in several organs — muscles, skin, and bones — and organ systems — immune, digestive, reproductive, and central nervous systems.<a href="#ref-2" id="ref-link-2" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Vallee BL, Falchuk KH. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/8419966" target="\_blank" rel="noopener noreferrer"&gt;The biochemical basis of zinc physiology.
&lt;/a&gt;&lt;/p&gt;Physiol Rev (1993-Jan)&lt;/div&gt;'>[2]</a> Diarrhea is a common symptom of zinc deficiency in infants, whereas poor growth and frequent infections are more common symptoms in children.<a href="#ref-36" id="ref-link-36" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Hambidge M. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/10801941" target="\_blank" rel="noopener noreferrer"&gt;Human zinc deficiency.
&lt;/a&gt;&lt;/p&gt;J Nutr (2000-May)&lt;/div&gt;'>[36]</a><a href="#ref-37" id="ref-link-37" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Nazanin Roohani, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/23914218" target="\_blank" rel="noopener noreferrer"&gt;Zinc and its importance for human health: An integrative review
&lt;/a&gt;&lt;/p&gt;J Res Med Sci (2013 Feb)&lt;/div&gt;'>[37]</a><a href="#ref-38" id="ref-link-38" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Maxfield L, Shukla S, Crane JS. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/29630283" target="\_blank" rel="noopener noreferrer"&gt;Zinc Deficiency
&lt;/a&gt;&lt;/p&gt;StatPearls (2022-11)&lt;/div&gt;'>[38]</a><a href="#ref-39" id="ref-link-39" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;K Ryan Wessells, Kenneth H Brown. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/23209782" target="\_blank" rel="noopener noreferrer"&gt;Estimating the global prevalence of zinc deficiency: results based on zinc availability in national food supplies and the prevalence of stunting
&lt;/a&gt;&lt;/p&gt;PLoS One (2012)&lt;/div&gt;'>[39]</a> Zinc deficiency can also cause a loss of appetite and alter the sense of taste and smell.<a href="#ref-40" id="ref-link-40" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Shay NF, Mangian HF. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/10801965" target="\_blank" rel="noopener noreferrer"&gt;Neurobiology of zinc-influenced eating behavior.
&lt;/a&gt;&lt;/p&gt;J Nutr (2000-May)&lt;/div&gt;'>[40]</a><a href="#ref-38" id="ref-link-38" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Maxfield L, Shukla S, Crane JS. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/29630283" target="\_blank" rel="noopener noreferrer"&gt;Zinc Deficiency
&lt;/a&gt;&lt;/p&gt;StatPearls (2022-11)&lt;/div&gt;'>[38]</a> However, these symptoms are not specific to zinc deficiency and can be caused by other conditions. Therefore, a person who suspects zinc deficiency should consult a doctor for further tests.

What are the signs and symptoms of zinc deficiency?

In 2012, the estimated global prevalence of inadequate zinc intake across all ages — the proportion of the population who have a high risk of zinc deficiency — was approximately 17%.<a href="#ref-39" id="ref-link-39" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;K Ryan Wessells, Kenneth H Brown. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/23209782" target="\_blank" rel="noopener noreferrer"&gt;Estimating the global prevalence of zinc deficiency: results based on zinc availability in national food supplies and the prevalence of stunting
&lt;/a&gt;&lt;/p&gt;PLoS One (2012)&lt;/div&gt;'>[39]</a> However, the estimated prevalence varied widely among countries, reaching approximately 8% in high-income countries, and much higher in low-income and middle-income regions (e.g., approximately 26% in Sub-Saharan Africa and 30% in South Asia).<a href="#ref-39" id="ref-link-39" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;K Ryan Wessells, Kenneth H Brown. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/23209782" target="\_blank" rel="noopener noreferrer"&gt;Estimating the global prevalence of zinc deficiency: results based on zinc availability in national food supplies and the prevalence of stunting
&lt;/a&gt;&lt;/p&gt;PLoS One (2012)&lt;/div&gt;'>[39]</a> Recent work published in 2020 confirmed these high prevalence estimates of zinc deficiency in low-income and middle-income countries.<a href="#ref-41" id="ref-link-41" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Gupta S, Brazier AKM, Lowe NM. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/32627912" target="\_blank" rel="noopener noreferrer"&gt;Zinc deficiency in low- and middle-income countries: prevalence and approaches for mitigation.
&lt;/a&gt;&lt;/p&gt;J Hum Nutr Diet (2020-Oct)&lt;/div&gt;'>[41]</a>
Importantly, the estimated prevalence of zinc deficiency in children less than 5 years of age is also high (greater than 20%) in both high-income<a href="#ref-42" id="ref-link-42" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Vreugdenhil M, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/34835970" target="\_blank" rel="noopener noreferrer"&gt;Prevalence of Zinc Deficiency in Healthy 1-3-Year-Old Children from Three Western European Countries.
&lt;/a&gt;&lt;/p&gt;Nutrients (2021-Oct-22)&lt;/div&gt;'>[42]</a> and low-income/middle-income countries.<a href="#ref-41" id="ref-link-41" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Gupta S, Brazier AKM, Lowe NM. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/32627912" target="\_blank" rel="noopener noreferrer"&gt;Zinc deficiency in low- and middle-income countries: prevalence and approaches for mitigation.
&lt;/a&gt;&lt;/p&gt;J Hum Nutr Diet (2020-Oct)&lt;/div&gt;'>[41]</a>

How common is zinc deficiency?

<a href="/supplements/zma/" class="popover" data-tooltip="&lt;div&gt;&lt;h6&gt;ZMA&lt;/h6&gt;&lt;p&gt;ZMA stands for zinc, magnesium, and aspartate. ZMA is an easy way to supplement these two minerals and vitamin B6.&lt;/p&gt;&lt;/div&gt;">ZMA</a> is a supplement composed of zinc monomethionine aspartate, magnesium aspartate, and vitamin B6.<a href="#ref-43" id="ref-link-43" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Kerksick CM, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/30068354" target="\_blank" rel="noopener noreferrer"&gt;ISSN exercise &amp;amp; sports nutrition review update: research &amp;amp; recommendations
&lt;/a&gt;&lt;/p&gt;J Int Soc Sports Nutr (2018 Aug 1)&lt;/div&gt;'>[43]</a> The first study to assess the effect of supplementation with ZMA in humans was conducted by the manufacturer of this supplement and found that ZMA raised testosterone levels and increased muscle strength and power in athletes.<a href="#ref-44" id="ref-link-44" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Brilla et al. &lt;a href="http://wikigimnasio.com/wp-content/uploads/Effects-of-a-Novel-Zinc-Magnesium-Formulation-on-Hormones-and-Strength.pdf" target="\_blank" rel="noopener noreferrer"&gt;Effects of a Novel Zinc-Magnesium Formulation on Hormones and Strength
&lt;/a&gt;&lt;/p&gt;Journal of Exercise Physiology (2020)&lt;/div&gt;'>[44]</a> However, follow-up studies by independent groups do not support those initial findings.<a href="#ref-45" id="ref-link-45" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Wilborn CD, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/18500945" target="\_blank" rel="noopener noreferrer"&gt;Effects of Zinc Magnesium Aspartate (ZMA) Supplementation on Training Adaptations and Markers of Anabolism and Catabolism
&lt;/a&gt;&lt;/p&gt;J Int Soc Sports Nutr (2004 Dec 31)&lt;/div&gt;'>[45]</a><a href="#ref-46" id="ref-link-46" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Koehler K, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/17882141" target="\_blank" rel="noopener noreferrer"&gt;Serum testosterone and urinary excretion of steroid hormone metabolites after administration of a high-dose zinc supplement
&lt;/a&gt;&lt;/p&gt;Eur J Clin Nutr (2009 Jan)&lt;/div&gt;'>[46]</a>

What is ZMA?

Zinc is an essential mineral and has a multitude of biological roles because it is a functional component of over 300 enzymes that rely on zinc to be able to catalyze chemical reactions. Zinc also participates in the structure of important proteins and is involved in the regulation of gene expression.<a href="#ref-1" id="ref-link-1" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Institute of Medicine (US) Panel on Micronutrients. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/25057538" target="\_blank" rel="noopener noreferrer"&gt;Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc
&lt;/a&gt;&lt;/p&gt;&lt;/div&gt;'>[1]</a><a href="#ref-2" id="ref-link-2" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Vallee BL, Falchuk KH. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/8419966" target="\_blank" rel="noopener noreferrer"&gt;The biochemical basis of zinc physiology.
&lt;/a&gt;&lt;/p&gt;Physiol Rev (1993-Jan)&lt;/div&gt;'>[2]</a> 
Zinc is obtained from the diet. Oysters contain substantially more zinc than any other food, although red meat (e.g., beef, pork) and poultry provide the majority of zinc in the American diet. Other good sources of zinc are legumes, nuts, and dairy products.<a href="#ref-3" id="ref-link-3" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;&lt;a href="https://fdc.nal.usda.gov/fdc-app.html#/?component=1095" target="\_blank" rel="noopener noreferrer"&gt;FoodData Central Search Results
&lt;/a&gt;&lt;/p&gt;U.S. Department of Agriculture, Agricultural Research Service (2023)&lt;/div&gt;'>[3]</a> In some countries, the flours used in cereals are fortified with zinc.<a href="#ref-4" id="ref-link-4" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Brown KH, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/20629353" target="\_blank" rel="noopener noreferrer"&gt;Zinc fortification of cereal flours: current recommendations and research needs.
&lt;/a&gt;&lt;/p&gt;Food Nutr Bull (2010-Mar)&lt;/div&gt;'>[4]</a>

What is zinc?

Animal studies show that zinc deficiency is associated with low testosterone, abnormal testicular function, and infertility.<a href="#ref-47" id="ref-link-47" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Yamaguchi S, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/19541612" target="\_blank" rel="noopener noreferrer"&gt;Zinc is an essential trace element for spermatogenesis.
&lt;/a&gt;&lt;/p&gt;Proc Natl Acad Sci U S A (2009-Jun-30)&lt;/div&gt;'>[47]</a><a href="#ref-48" id="ref-link-48" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Croxford TP, McCormick NH, Kelleher SL. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/21248196" target="\_blank" rel="noopener noreferrer"&gt;Moderate zinc deficiency reduces testicular Zip6 and Zip10 abundance and impairs spermatogenesis in mice.
&lt;/a&gt;&lt;/p&gt;J Nutr (2011-Mar)&lt;/div&gt;'>[48]</a><a href="#ref-49" id="ref-link-49" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Merrells KJ, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/19222874" target="\_blank" rel="noopener noreferrer"&gt;Relationship between abnormal sperm morphology induced by dietary zinc deficiency and lipid composition in testes of growing rats.
&lt;/a&gt;&lt;/p&gt;Br J Nutr (2009-Jul)&lt;/div&gt;'>[49]</a><a href="#ref-50" id="ref-link-50" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Te L, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/36577241" target="\_blank" rel="noopener noreferrer"&gt;Correlation between serum zinc and testosterone: A systematic review.
&lt;/a&gt;&lt;/p&gt;J Trace Elem Med Biol (2023-Mar)&lt;/div&gt;'>[50]</a> Some human studies have reported similar observations,<a href="#ref-50" id="ref-link-50" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Te L, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/36577241" target="\_blank" rel="noopener noreferrer"&gt;Correlation between serum zinc and testosterone: A systematic review.
&lt;/a&gt;&lt;/p&gt;J Trace Elem Med Biol (2023-Mar)&lt;/div&gt;'>[50]</a><a href="#ref-51" id="ref-link-51" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;C D Hunt, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/1609752" target="\_blank" rel="noopener noreferrer"&gt;Effects of dietary zinc depletion on seminal volume and zinc loss, serum testosterone concentrations, and sperm morphology in young men
&lt;/a&gt;&lt;/p&gt;Am J Clin Nutr (1992 Jul)&lt;/div&gt;'>[51]</a><a href="#ref-52" id="ref-link-52" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;A Taravati, F Tohidi. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/26541500" target="\_blank" rel="noopener noreferrer"&gt;Association between seminal plasma zinc level and asthenozoospermia: a meta-analysis study
&lt;/a&gt;&lt;/p&gt;Andrologia (2016 Aug)&lt;/div&gt;'>[52]</a><a href="#ref-53" id="ref-link-53" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Jiang Zhao, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/26932683" target="\_blank" rel="noopener noreferrer"&gt;Zinc levels in seminal plasma and their correlation with male infertility: A systematic review and meta-analysis
&lt;/a&gt;&lt;/p&gt;Sci Rep (2016 Mar 2)&lt;/div&gt;'>[53]</a> but because of the lack of clinical trials, conclusions about the effect of zinc supplementation on sperm health or fertility aren’t currently possible.<a href="#ref-54" id="ref-link-54" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Netter A, Hartoma R, Nahoul K. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/7271365" target="\_blank" rel="noopener noreferrer"&gt;Effect of zinc administration on plasma testosterone, dihydrotestosterone, and sperm count
&lt;/a&gt;&lt;/p&gt;Arch Androl (1981 Aug)&lt;/div&gt;'>[54]</a><a href="#ref-55" id="ref-link-55" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Prasad AS, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/8875519" target="\_blank" rel="noopener noreferrer"&gt;Zinc status and serum testosterone levels of healthy adults
&lt;/a&gt;&lt;/p&gt;Nutrition (1996 May)&lt;/div&gt;'>[55]</a><a href="#ref-53" id="ref-link-53" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Jiang Zhao, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/26932683" target="\_blank" rel="noopener noreferrer"&gt;Zinc levels in seminal plasma and their correlation with male infertility: A systematic review and meta-analysis
&lt;/a&gt;&lt;/p&gt;Sci Rep (2016 Mar 2)&lt;/div&gt;'>[53]</a><a href="#ref-56" id="ref-link-56" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Shahid MN, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/34483894" target="\_blank" rel="noopener noreferrer"&gt;Effectiveness of Pharmacological Intervention Among Men with Infertility: A Systematic Review and Network Meta-Analysis.
&lt;/a&gt;&lt;/p&gt;Front Pharmacol (2021)&lt;/div&gt;'>[56]</a>

Does supplementation with zinc improve sperm health or fertility?

Zinc deficiency is common in people with <a href="/conditions/human-immunodeficiency-virus/" class="popover" data-tooltip="&lt;div&gt;&lt;h6&gt;Human Immunodeficiency Virus&lt;/h6&gt;&lt;p&gt;Human immunodeficiency virus (HIV) is a virus that attacks cells within the immune system, which results in a decreased ability to fight off infection. An HIV infection can progress to a disease called Acquired Immunodeficiency Syndrome (AIDS).&lt;/p&gt;&lt;/div&gt;">human immunodeficiency virus</a> (HIV)<a href="#ref-57" id="ref-link-57" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Clara Y Jones, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/17019373" target="\_blank" rel="noopener noreferrer"&gt;Micronutrient levels and HIV disease status in HIV-infected patients on highly active antiretroviral therapy in the Nutrition for Healthy Living cohort
&lt;/a&gt;&lt;/p&gt;J Acquir Immune Defic Syndr (2006 Dec 1)&lt;/div&gt;'>[57]</a><a href="#ref-58" id="ref-link-58" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Baum MK, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/12942385" target="\_blank" rel="noopener noreferrer"&gt;Zinc status in human immunodeficiency virus type 1 infection and illicit drug use.
&lt;/a&gt;&lt;/p&gt;Clin Infect Dis (2003)&lt;/div&gt;'>[58]</a> and is associated with disease progression.<a href="#ref-59" id="ref-link-59" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;N M Graham, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/1890606" target="\_blank" rel="noopener noreferrer"&gt;Relationship of serum copper and zinc levels to HIV-1 seropositivity and progression to AIDS
&lt;/a&gt;&lt;/p&gt;J Acquir Immune Defic Syndr (1988) (1991)&lt;/div&gt;'>[59]</a><a href="#ref-58" id="ref-link-58" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Baum MK, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/12942385" target="\_blank" rel="noopener noreferrer"&gt;Zinc status in human immunodeficiency virus type 1 infection and illicit drug use.
&lt;/a&gt;&lt;/p&gt;Clin Infect Dis (2003)&lt;/div&gt;'>[58]</a> Accordingly, some studies show that supplementation with zinc may delay immunological failure and reduce the occurrence of opportunistic infections in participants with both zinc deficiency and HIV.<a href="#ref-60" id="ref-link-60" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Baum MK, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/20455705" target="\_blank" rel="noopener noreferrer"&gt;Randomized, controlled clinical trial of zinc supplementation to prevent immunological failure in HIV-infected adults.
&lt;/a&gt;&lt;/p&gt;Clin Infect Dis (2010-Jun-15)&lt;/div&gt;'>[60]</a><a href="#ref-61" id="ref-link-61" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Mocchegiani E, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/8582783" target="\_blank" rel="noopener noreferrer"&gt;Benefit of oral zinc supplementation as an adjunct to zidovudine (AZT) therapy against opportunistic infections in AIDS.
&lt;/a&gt;&lt;/p&gt;Int J Immunopharmacol (1995-Sep)&lt;/div&gt;'>[61]</a><a href="#ref-62" id="ref-link-62" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Zeng L, Zhang L. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/21895892" target="\_blank" rel="noopener noreferrer"&gt;Efficacy and safety of zinc supplementation for adults, children and pregnant women with HIV infection: systematic review.
&lt;/a&gt;&lt;/p&gt;Trop Med Int Health (2011-Dec)&lt;/div&gt;'>[62]</a>

Does supplementation with zinc help people with <a href="/conditions/human-immunodeficiency-virus/" class="popover" data-tooltip="&lt;div&gt;&lt;h6&gt;Human Immunodeficiency Virus&lt;/h6&gt;&lt;p&gt;Human immunodeficiency virus (HIV) is a virus that attacks cells within the immune system, which results in a decreased ability to fight off infection. An HIV infection can progress to a disease called Acquired Immunodeficiency Syndrome (AIDS).&lt;/p&gt;&lt;/div&gt;">human immunodeficiency virus</a> (HIV)?

The potential benefits of supplementation with zinc are largely dependent on the individual’s zinc status. Therefore, supplementation with zinc is unlikely to provide a benefit if zinc levels are already adequate and the person is not zinc deficient.<a href="#ref-5" id="ref-link-5" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Seet RC, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/21840002" target="\_blank" rel="noopener noreferrer"&gt;Oral zinc supplementation does not improve oxidative stress or vascular function in patients with type 2 diabetes with normal zinc levels
&lt;/a&gt;&lt;/p&gt;Atherosclerosis (2011 Nov)&lt;/div&gt;'>[5]</a> One exception to this rule may be respiratory tract infections and the common cold, conditions in which supplementation with zinc has been shown to reduce the duration of illness.<a href="#ref-6" id="ref-link-6" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Jennifer Hunter, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/34728441" target="\_blank" rel="noopener noreferrer"&gt;Zinc for the prevention or treatment of acute viral respiratory tract infections in adults: a rapid systematic review and meta-analysis of randomised controlled trials
&lt;/a&gt;&lt;/p&gt;BMJ Open (2021 Nov 2)&lt;/div&gt;'>[6]</a><a href="#ref-7" id="ref-link-7" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Min Xian Wang, Shwe Sin Win, Junxiong Pang. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/32342851" target="\_blank" rel="noopener noreferrer"&gt;Zinc Supplementation Reduces Common Cold Duration among Healthy Adults: A Systematic Review of Randomized Controlled Trials with Micronutrients Supplementation
&lt;/a&gt;&lt;/p&gt;Am J Trop Med Hyg (2020 Jul)&lt;/div&gt;'>[7]</a><a href="#ref-8" id="ref-link-8" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Harri Hemilä. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/21769305" target="\_blank" rel="noopener noreferrer"&gt;Zinc lozenges may shorten the duration of colds: a systematic review
&lt;/a&gt;&lt;/p&gt;Open Respir Med J (2011)&lt;/div&gt;'>[8]</a> In children, zinc may help prevent <a href="/conditions/pneumonia/" class="popover" data-tooltip="&lt;div&gt;&lt;h6&gt;Pneumonia&lt;/h6&gt;&lt;p&gt;Pneumonia is an infection that inflames the air sacs and lower airways of the lungs, causing them to fill with fluid. Signs and symptoms of pneumonia include fever and chills, difficulty breathing, fatigue, and cough (with or without mucus). Cases caused by bacteria are treated with antibiotics.&lt;/p&gt;&lt;/div&gt;">pneumonia</a>.<a href="#ref-9" id="ref-link-9" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Wang L, Song Y. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/28488366" target="\_blank" rel="noopener noreferrer"&gt;Efficacy of zinc given as an adjunct to the treatment of severe pneumonia: A meta-analysis of randomized, double-blind and placebo-controlled trials.
&lt;/a&gt;&lt;/p&gt;Clin Respir J (2018-Mar)&lt;/div&gt;'>[9]</a><a href="#ref-10" id="ref-link-10" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Lassi ZS, Moin A, Bhutta ZA. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/27915460" target="\_blank" rel="noopener noreferrer"&gt;Zinc supplementation for the prevention of pneumonia in children aged 2 months to 59 months.
&lt;/a&gt;&lt;/p&gt;Cochrane Database Syst Rev (2016-Dec-04)&lt;/div&gt;'>[10]</a> However, further high-quality studies are needed to bolster the evidence in this field.
Supplementation with zinc has been shown to improve depressive symptoms<a href="#ref-11" id="ref-link-11" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Somaye Yosaee, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/32829928" target="\_blank" rel="noopener noreferrer"&gt;Zinc in depression: From development to treatment: A comparative/ dose response meta-analysis of observational studies and randomized controlled trials
&lt;/a&gt;&lt;/p&gt;Gen Hosp Psychiatry (Jan-Feb 2022)&lt;/div&gt;'>[11]</a><a href="#ref-12" id="ref-link-12" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Sawada T, Yokoi K. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/20087376" target="\_blank" rel="noopener noreferrer"&gt;Effect of zinc supplementation on mood states in young women: a pilot study
&lt;/a&gt;&lt;/p&gt;Eur J Clin Nutr (2010 Mar)&lt;/div&gt;'>[12]</a> and markers of glycemic control and blood lipids, particularly in people with chronic disease.<a href="#ref-13" id="ref-link-13" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Laura M Pompano, Erick Boy. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/32722790" target="\_blank" rel="noopener noreferrer"&gt;Effects of Dose and Duration of Zinc Interventions on Risk Factors for Type 2 Diabetes and Cardiovascular Disease: A Systematic Review and Meta-Analysis
&lt;/a&gt;&lt;/p&gt;Adv Nutr (2020 Jul 28)&lt;/div&gt;'>[13]</a><a href="#ref-14" id="ref-link-14" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Kelishadi R, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/21028969" target="\_blank" rel="noopener noreferrer"&gt;Effect of zinc supplementation on markers of insulin resistance, oxidative stress, and inflammation among prepubescent children with metabolic syndrome
&lt;/a&gt;&lt;/p&gt;Metab Syndr Relat Disord (2010 Dec)&lt;/div&gt;'>[14]</a><a href="#ref-15" id="ref-link-15" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Hashemipour M, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/20045801" target="\_blank" rel="noopener noreferrer"&gt;Effect of zinc supplementation on insulin resistance and components of the metabolic syndrome in prepubertal obese children
&lt;/a&gt;&lt;/p&gt;Hormones (Athens) (2009 Oct-Dec)&lt;/div&gt;'>[15]</a> Supplementation with zinc may also improve severe acne, but higher-quality trials are needed to bolster the current evidence.<a href="#ref-16" id="ref-link-16" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Brittany E Yee, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/32860489" target="\_blank" rel="noopener noreferrer"&gt;Serum zinc levels and efficacy of zinc treatment in acne vulgaris: A systematic review and meta-analysis
&lt;/a&gt;&lt;/p&gt;Dermatol Ther (2020 Aug 29)&lt;/div&gt;'>[16]</a><a href="#ref-17" id="ref-link-17" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Liu H, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/32356369" target="\_blank" rel="noopener noreferrer"&gt;Topical azelaic acid, salicylic acid, nicotinamide, sulphur, zinc and fruit acid (alpha-hydroxy acid) for acne.
&lt;/a&gt;&lt;/p&gt;Cochrane Database Syst Rev (2020-May-01)&lt;/div&gt;'>[17]</a>

What are zinc’s main benefits?

It is possible that ZMA can cause weird dreams, and the anecdotes support this; however, since this has not been directly investigated the best 'proof' that can be given is weak.

<a href="/supplements/zma/" class="popover" data-tooltip="&lt;div&gt;&lt;h6&gt;ZMA&lt;/h6&gt;&lt;p&gt;ZMA stands for zinc, magnesium, and aspartate. ZMA is an easy way to supplement these two minerals and vitamin B6.&lt;/p&gt;&lt;/div&gt;">ZMA</a> is a proprietary blend of <a href="/supplements/zinc/" class="popover" data-tooltip="&lt;div&gt;&lt;h6&gt;Zinc&lt;/h6&gt;&lt;p&gt;Zinc is an essential mineral that is critical for the function of hundreds of enzymes. Consequently, it plays many roles, including in antioxidant enzymes, brain function, and the immune system. Zinc is most commonly taken to reduce the duration of respiratory infections and the common cold.&lt;/p&gt;&lt;/div&gt;">Zinc</a> bound to monomethionine, <a href="/supplements/magnesium/" class="popover" data-tooltip="&lt;div&gt;&lt;h6&gt;Magnesium&lt;/h6&gt;&lt;p&gt;Magnesium is an essential dietary mineral that is involved in energy production, nervous system function, blood pressure regulation, and blood glucose control. A lack of magnesium in the diet — which is common in modern societies — is associated with an increased risk of diabetes, cardiovascular disease, and other health conditions.&lt;/p&gt;&lt;/div&gt;">Magnesium</a> bound to aspartate, and the vitamin B6 (Pyridoxine). It is sometimes reported to give users 'weird, vivid dreams'.
This claim has not been investigated much, but a pilot study<a href="#ref-34" id="ref-link-34" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Ebben M, Lequerica A, Spielman A. &lt;a href="https://www.ncbi.nlm.nih.gov/pubmed/11883552" target="\_blank" rel="noopener noreferrer"&gt;Effects of pyridoxine on dreaming: a preliminary study
&lt;/a&gt;&lt;/p&gt;Percept Mot Skills (2002 Feb)&lt;/div&gt;'>[34]</a> suggests that a dose of 250mg pyridoxine can alter dream perception in college aged men, through a hypothesized increased conversion of tryptophan to serotonin. This dose of B6, however, is much higher than that occurring in ZMA products; which tends to range in the 10-50mg range and usually at the lower end.
One other study has reported synergism between B6 and Magnesium in regards to anxiety reduction, when the subjects were women experiencing PMS;<a href="#ref-35" id="ref-link-35" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;De Souza MC, et al. &lt;a href="https://www.ncbi.nlm.nih.gov/pubmed/10746516" target="\_blank" rel="noopener noreferrer"&gt;A synergistic effect of a daily supplement for 1 month of 200 mg magnesium plus 50 mg vitamin B6 for the relief of anxiety-related premenstrual symptoms: a randomized, double-blind, crossover study
&lt;/a&gt;&lt;/p&gt;J Womens Health Gend Based Med (2000 Mar)&lt;/div&gt;'>[35]</a> it is theoretically possible that the ZMA formulation enhances the actions of pyridoxine allowing the previous research's results to be relevant.

Does ZMA cause weird dreams?

In adults, some studies show that when zinc and iron are co-ingested, zinc can reduce the intestinal absorption of iron or the incorporation of iron into red blood cells, particularly when zinc is ingested in higher amounts.<a href="#ref-20" id="ref-link-20" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Bjørklund G, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/28347462" target="\_blank" rel="noopener noreferrer"&gt;Interactions of iron with manganese, zinc, chromium, and selenium as related to prophylaxis and treatment of iron deficiency.
&lt;/a&gt;&lt;/p&gt;J Trace Elem Med Biol (2017-May)&lt;/div&gt;'>[20]</a><a href="#ref-63" id="ref-link-63" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Olivares M, Pizarro F, Ruz M. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/17873388" target="\_blank" rel="noopener noreferrer"&gt;Zinc inhibits nonheme iron bioavailability in humans
&lt;/a&gt;&lt;/p&gt;Biol Trace Elem Res (2007 Summer)&lt;/div&gt;'>[63]</a><a href="#ref-64" id="ref-link-64" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Olivares M, Pizarro F, Ruz M. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/17350802" target="\_blank" rel="noopener noreferrer"&gt;New insights about iron bioavailability inhibition by zinc
&lt;/a&gt;&lt;/p&gt;Nutrition (2007 Apr)&lt;/div&gt;'>[64]</a> In women with iron deficiency and in infants, some evidence also shows that supplementation with zinc can lower plasma ferritin (a biomarker for the body’s iron stores that is used to diagnose iron deficiency).<a href="#ref-65" id="ref-link-65" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Marena Ceballos-Rasgado, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/36055780" target="\_blank" rel="noopener noreferrer"&gt;Adverse Effects of Excessive Zinc Intake in Infants and Children Aged 0-3 Years: A Systematic Review and Meta-Analysis
&lt;/a&gt;&lt;/p&gt;Adv Nutr (2022 Dec 22)&lt;/div&gt;'>[65]</a><a href="#ref-66" id="ref-link-66" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Donangelo CM, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/12097660" target="\_blank" rel="noopener noreferrer"&gt;Supplemental zinc lowers measures of iron status in young women with low iron reserves
&lt;/a&gt;&lt;/p&gt;J Nutr (2002 Jul)&lt;/div&gt;'>[66]</a> Consequently, it is sometimes claimed that excess zinc intake can cause iron deficiency. 
However, zinc appears to impair iron absorption only when zinc and iron are co-ingested in an aqueous solution.<a href="#ref-20" id="ref-link-20" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Bjørklund G, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/28347462" target="\_blank" rel="noopener noreferrer"&gt;Interactions of iron with manganese, zinc, chromium, and selenium as related to prophylaxis and treatment of iron deficiency.
&lt;/a&gt;&lt;/p&gt;J Trace Elem Med Biol (2017-May)&lt;/div&gt;'>[20]</a><a href="#ref-63" id="ref-link-63" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Olivares M, Pizarro F, Ruz M. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/17873388" target="\_blank" rel="noopener noreferrer"&gt;Zinc inhibits nonheme iron bioavailability in humans
&lt;/a&gt;&lt;/p&gt;Biol Trace Elem Res (2007 Summer)&lt;/div&gt;'>[63]</a><a href="#ref-64" id="ref-link-64" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Olivares M, Pizarro F, Ruz M. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/17350802" target="\_blank" rel="noopener noreferrer"&gt;New insights about iron bioavailability inhibition by zinc
&lt;/a&gt;&lt;/p&gt;Nutrition (2007 Apr)&lt;/div&gt;'>[64]</a> In contrast, when zinc and iron are mixed with food, there is no inhibitory effect of zinc on intestinal iron absorption or the incorporation of orally ingested iron into red blood cells.<a href="#ref-67" id="ref-link-67" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Rossander-Hultén L, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/2058577" target="\_blank" rel="noopener noreferrer"&gt;Competitive inhibition of iron absorption by manganese and zinc in humans.
&lt;/a&gt;&lt;/p&gt;Am J Clin Nutr (1991-Jul)&lt;/div&gt;'>[67]</a><a href="#ref-20" id="ref-link-20" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Bjørklund G, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/28347462" target="\_blank" rel="noopener noreferrer"&gt;Interactions of iron with manganese, zinc, chromium, and selenium as related to prophylaxis and treatment of iron deficiency.
&lt;/a&gt;&lt;/p&gt;J Trace Elem Med Biol (2017-May)&lt;/div&gt;'>[20]</a><a href="#ref-68" id="ref-link-68" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Olivares M, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/22760642" target="\_blank" rel="noopener noreferrer"&gt;Effect of increasing concentrations of zinc on the absorption of iron from iron-fortified milk
&lt;/a&gt;&lt;/p&gt;Biol Trace Elem Res (2012 Dec)&lt;/div&gt;'>[68]</a><a href="#ref-69" id="ref-link-69" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Olivares M, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/22297381" target="\_blank" rel="noopener noreferrer"&gt;Acute inhibition of iron bioavailability by zinc: studies in humans
&lt;/a&gt;&lt;/p&gt;Biometals (2012 Aug)&lt;/div&gt;'>[69]</a><a href="#ref-70" id="ref-link-70" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Palsa Kondaiah, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/31412634" target="\_blank" rel="noopener noreferrer"&gt;Iron and Zinc Homeostasis and Interactions: Does Enteric Zinc Excretion Cross-Talk with Intestinal Iron Absorption?
&lt;/a&gt;&lt;/p&gt;Nutrients (2019 Aug 13)&lt;/div&gt;'>[70]</a><a href="#ref-71" id="ref-link-71" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Fischer Walker C, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/16002793" target="\_blank" rel="noopener noreferrer"&gt;Interactive effects of iron and zinc on biochemical and functional outcomes in supplementation trials.
&lt;/a&gt;&lt;/p&gt;Am J Clin Nutr (2005-Jul)&lt;/div&gt;'>[71]</a> Additionally, the majority of human studies in adults find no effect of orally ingested zinc on plasma <a href="/outcomes/ferritin/" class="popover" data-tooltip="&lt;div&gt;&lt;h6&gt;Ferritin&lt;/h6&gt;&lt;p&gt;Ferritin is the primary protein for storing iron in the body. Ferritin levels are generally used as an indirect measure of iron levels (e.g., for diagnosis of anemia). However, in some conditions, ferritin levels can remain high when iron levels are low.&lt;/p&gt;&lt;/div&gt;">ferritin</a> (body iron stores).<a href="#ref-20" id="ref-link-20" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Bjørklund G, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/28347462" target="\_blank" rel="noopener noreferrer"&gt;Interactions of iron with manganese, zinc, chromium, and selenium as related to prophylaxis and treatment of iron deficiency.
&lt;/a&gt;&lt;/p&gt;J Trace Elem Med Biol (2017-May)&lt;/div&gt;'>[20]</a><a href="#ref-71" id="ref-link-71" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Fischer Walker C, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/16002793" target="\_blank" rel="noopener noreferrer"&gt;Interactive effects of iron and zinc on biochemical and functional outcomes in supplementation trials.
&lt;/a&gt;&lt;/p&gt;Am J Clin Nutr (2005-Jul)&lt;/div&gt;'>[71]</a> Therefore, the risk of zinc-induced iron deficiency is probably negligible in most people.
It’s important to note that reduced absorption of dietary iron is not the same as iron deficiency (low iron stores as indicated by low plasma ferritin) because the body stores iron to help regulate iron absorption in line with the body’s need for iron. Also, note that iron deficiency is not the same as anemia, a condition characterized by low <a href="/outcomes/red-blood-cell-count/" class="popover" data-tooltip="&lt;div&gt;&lt;h6&gt;Red Blood Cell Count&lt;/h6&gt;&lt;p&gt;Red blood cell count refers to total erythrocytes in serum, and is usually measured in toxicology testing or some instances of anemia. Although higher than average levels of red blood cells can needlessly increase blood pressure, it supports aerobic exercise and oxygen delivery.&lt;/p&gt;&lt;/div&gt;">red blood cell count</a> and low <a href="/outcomes/hemoglobin/" class="popover" data-tooltip="&lt;div&gt;&lt;h6&gt;Hemoglobin&lt;/h6&gt;&lt;p&gt;Hemoglobin is the protein that carries oxygen in red blood cells for delivery to tissues throughout the body.&lt;/p&gt;&lt;/div&gt;">hemoglobin</a> concentrations. Indeed, iron deficiency can cause anemia — specifically <a href="/conditions/iron-deficiency-anemia/" class="popover" data-tooltip="&lt;div&gt;&lt;h6&gt;Iron Deficiency Anemia&lt;/h6&gt;&lt;p&gt;Iron deficiency anemia occurs when the body does not have enough iron to produce healthy red blood cells to transport oxygen in the blood. Iron deficiency anemia can be caused by excessive blood loss or reduced iron absorption or intake. It can be treated with oral iron supplementation, though there is a wide range of individual tolerance for, and effectiveness of, iron supplements.&lt;/p&gt;&lt;/div&gt;">iron deficiency anemia</a> — but it is not always sufficient to do so.

Does excess zinc intake cause iron deficiency?

In the short term, consuming zinc in excess of the recommended upper limit (40 mg/day)<a href="#ref-1" id="ref-link-1" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Institute of Medicine (US) Panel on Micronutrients. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/25057538" target="\_blank" rel="noopener noreferrer"&gt;Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc
&lt;/a&gt;&lt;/p&gt;&lt;/div&gt;'>[1]</a> can result in gastrointestinal symptoms (e.g., abdominal pain, nausea, vomiting, diarrhea).<a href="#ref-1" id="ref-link-1" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Institute of Medicine (US) Panel on Micronutrients. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/25057538" target="\_blank" rel="noopener noreferrer"&gt;Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc
&lt;/a&gt;&lt;/p&gt;&lt;/div&gt;'>[1]</a><a href="#ref-18" id="ref-link-18" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Singh M, Das RR. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/21328251" target="\_blank" rel="noopener noreferrer"&gt;Zinc for the common cold
&lt;/a&gt;&lt;/p&gt;Cochrane Database Syst Rev (2011 Feb 16)&lt;/div&gt;'>[18]</a> In the long term, excessive zinc intake has been associated with copper deficiency and iron deficiency, as well as suppression of the immune system.<a href="#ref-19" id="ref-link-19" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Dorota Skrajnowska, Barbara Bobrowska-Korczak. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/31546724" target="\_blank" rel="noopener noreferrer"&gt;Role of Zinc in Immune System and Anti-Cancer Defense Mechanisms
&lt;/a&gt;&lt;/p&gt;Nutrients (2019 Sep 22)&lt;/div&gt;'>[19]</a><a href="#ref-20" id="ref-link-20" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Bjørklund G, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/28347462" target="\_blank" rel="noopener noreferrer"&gt;Interactions of iron with manganese, zinc, chromium, and selenium as related to prophylaxis and treatment of iron deficiency.
&lt;/a&gt;&lt;/p&gt;J Trace Elem Med Biol (2017-May)&lt;/div&gt;'>[20]</a><a href="#ref-21" id="ref-link-21" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Chandra RK. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/6471270" target="\_blank" rel="noopener noreferrer"&gt;Excessive intake of zinc impairs immune responses
&lt;/a&gt;&lt;/p&gt;JAMA (1984 Sep 21)&lt;/div&gt;'>[21]</a> Also, the application of intranasal zinc has been reported to cause a loss of smell in some people.<a href="#ref-22" id="ref-link-22" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Terence M Davidson, Wendy M Smith. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/20644061" target="\_blank" rel="noopener noreferrer"&gt;The Bradford Hill criteria and zinc-induced anosmia: a causality analysis
&lt;/a&gt;&lt;/p&gt;Arch Otolaryngol Head Neck Surg (2010 Jul)&lt;/div&gt;'>[22]</a>

What are zinc’s main drawbacks?

The potential benefits derived from supplementation with zinc seem to be at least partly attributable to zinc’s anti-inflammatory and antioxidant properties.<a href="#ref-2" id="ref-link-2" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Vallee BL, Falchuk KH. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/8419966" target="\_blank" rel="noopener noreferrer"&gt;The biochemical basis of zinc physiology.
&lt;/a&gt;&lt;/p&gt;Physiol Rev (1993-Jan)&lt;/div&gt;'>[2]</a><a href="#ref-23" id="ref-link-23" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Prasad AS. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/18385818" target="\_blank" rel="noopener noreferrer"&gt;Zinc in human health: effect of zinc on immune cells.
&lt;/a&gt;&lt;/p&gt;Mol Med (2008)&lt;/div&gt;'>[23]</a><a href="#ref-24" id="ref-link-24" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Ananda S Prasad. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/18054190" target="\_blank" rel="noopener noreferrer"&gt;Clinical, immunological, anti-inflammatory and antioxidant roles of zinc
&lt;/a&gt;&lt;/p&gt;Exp Gerontol (2008 May)&lt;/div&gt;'>[24]</a><a href="#ref-25" id="ref-link-25" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Bao B, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/20427734" target="\_blank" rel="noopener noreferrer"&gt;Zinc decreases C-reactive protein, lipid peroxidation, and inflammatory cytokines in elderly subjects: a potential implication of zinc as an atheroprotective agent
&lt;/a&gt;&lt;/p&gt;Am J Clin Nutr (2010 Jun)&lt;/div&gt;'>[25]</a> 
Adequate dietary intake of zinc is essential for proper growth and development during pregnancy and throughout infancy, childhood, and adulthood.<a href="#ref-2" id="ref-link-2" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Vallee BL, Falchuk KH. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/8419966" target="\_blank" rel="noopener noreferrer"&gt;The biochemical basis of zinc physiology.
&lt;/a&gt;&lt;/p&gt;Physiol Rev (1993-Jan)&lt;/div&gt;'>[2]</a><a href="#ref-26" id="ref-link-26" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;National Research Council (US) Subcommittee on the Tenth Edition of the Recommended Dietary Allowances. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/25144070" target="\_blank" rel="noopener noreferrer"&gt;Recommended Dietary Allowances: 10th Edition
&lt;/a&gt;&lt;/p&gt;&lt;/div&gt;'>[26]</a> Additionally, zinc is required for normal development, activity, and function of both innate and adaptive immune cells;<a href="#ref-19" id="ref-link-19" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Dorota Skrajnowska, Barbara Bobrowska-Korczak. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/31546724" target="\_blank" rel="noopener noreferrer"&gt;Role of Zinc in Immune System and Anti-Cancer Defense Mechanisms
&lt;/a&gt;&lt;/p&gt;Nutrients (2019 Sep 22)&lt;/div&gt;'>[19]</a><a href="#ref-27" id="ref-link-27" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Maria Maares, Hajo Haase. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/27021581" target="\_blank" rel="noopener noreferrer"&gt;Zinc and immunity: An essential interrelation
&lt;/a&gt;&lt;/p&gt;Arch Biochem Biophys (2016 Dec 1)&lt;/div&gt;'>[27]</a> proper function of pancreatic beta-cells and glucose uptake;<a href="#ref-28" id="ref-link-28" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Anatoly V Skalny, Michael Aschner, Alexey A Tinkov. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/34112355" target="\_blank" rel="noopener noreferrer"&gt;Zinc
&lt;/a&gt;&lt;/p&gt;Adv Food Nutr Res (2021)&lt;/div&gt;'>[28]</a> and spermatogenesis and normal sperm physiology (e.g., sperm motility).<a href="#ref-29" id="ref-link-29" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Kinga Skoracka, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/32397485" target="\_blank" rel="noopener noreferrer"&gt;Diet and Nutritional Factors in Male (In)fertility-Underestimated Factors
&lt;/a&gt;&lt;/p&gt;J Clin Med (2020 May 9)&lt;/div&gt;'>[29]</a> 
In the brain, zinc ions inhibit <a href="https://examine.com/topics/nmda-neurotransmission/">N-methyl-D-aspartate</a> (NMDA) receptors,<a href="#ref-30" id="ref-link-30" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Stacy A Amico-Ruvio, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/21504727" target="\_blank" rel="noopener noreferrer"&gt;Zinc effects on NMDA receptor gating kinetics
&lt;/a&gt;&lt;/p&gt;Biophys J (2011 Apr 20)&lt;/div&gt;'>[30]</a> which is relevant to depression because this condition is characterized by elevated glutamatergic neurotransmission (to which NMDA receptors contribute).<a href="#ref-31" id="ref-link-31" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Adejoke Yetunde Onaolapo, Olakunle James Onaolapo. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/34327123" target="\_blank" rel="noopener noreferrer"&gt;Glutamate and depression: Reflecting a deepening knowledge of the gut and brain effects of a ubiquitous molecule
&lt;/a&gt;&lt;/p&gt;World J Psychiatry (2021 Jul 19)&lt;/div&gt;'>[31]</a> Zinc may also benefit depression by increasing brain-derived neurotrophic factor levels.<a href="#ref-32" id="ref-link-32" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Jafari F, Amani R, Tarrahi MJ. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/31154571" target="\_blank" rel="noopener noreferrer"&gt;Effect of Zinc Supplementation on Physical and Psychological Symptoms, Biomarkers of Inflammation, Oxidative Stress, and Brain-Derived Neurotrophic Factor in Young Women with Premenstrual Syndrome: a Randomized, Double-Blind, Placebo-Controlled Trial
&lt;/a&gt;&lt;/p&gt;Biol Trace Elem Res (2019 Jun 2)&lt;/div&gt;'>[32]</a><a href="#ref-33" id="ref-link-33" class="ref-link popover" data-tooltip='&lt;div&gt;&lt;p class="mb-3"&gt;Solati Z, et al. &lt;a href="https://pubmed.ncbi.nlm.nih.gov/24621065" target="\_blank" rel="noopener noreferrer"&gt;Zinc monotherapy increases serum brain-derived neurotrophic factor (BDNF) levels and decreases depressive symptoms in overweight or obese subjects: A double-blind, randomized, placebo-controlled trial
&lt;/a&gt;&lt;/p&gt;Nutr Neurosci (2014 Jan 7)&lt;/div&gt;'>[33]</a>

How does zinc work?

Zinc

When it comes to increasing your testosterone, <a href="https://examine.com/nutrition/ten-tips-for-better-sleep/">quality sleep</a>, physical activity, and weight management come first. A few supplements can help sustain healthy testosterone levels, but most supplements marketed as testosterone boosters don't work, though some can make you believe they do by boosting your libido.

How can you increase testosterone naturally?

Immunity & Infectious Disease

Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc

The biochemical basis of zinc physiology.

FoodData Central Search Results

Zinc fortification of cereal flours: current recommendations and research needs.

Oral zinc supplementation does not improve oxidative stress or vascular function in patients with type 2 diabetes with normal zinc levels

Zinc for the prevention or treatment of acute viral respiratory tract infections in adults: a rapid systematic review and meta-analysis of randomised controlled trials

Zinc Supplementation Reduces Common Cold Duration among Healthy Adults: A Systematic Review of Randomized Controlled Trials with Micronutrients Supplementation

Zinc lozenges may shorten the duration of colds: a systematic review

Efficacy of zinc given as an adjunct to the treatment of severe pneumonia: A meta-analysis of randomized, double-blind and placebo-controlled trials.

Zinc supplementation for the prevention of pneumonia in children aged 2 months to 59 months.

Zinc in depression: From development to treatment: A comparative/ dose response meta-analysis of observational studies and randomized controlled trials

Effect of zinc supplementation on mood states in young women: a pilot study

Effects of Dose and Duration of Zinc Interventions on Risk Factors for Type 2 Diabetes and Cardiovascular Disease: A Systematic Review and Meta-Analysis

Effect of zinc supplementation on markers of insulin resistance, oxidative stress, and inflammation among prepubescent children with metabolic syndrome

Effect of zinc supplementation on insulin resistance and components of the metabolic syndrome in prepubertal obese children

Serum zinc levels and efficacy of zinc treatment in acne vulgaris: A systematic review and meta-analysis

Topical azelaic acid, salicylic acid, nicotinamide, sulphur, zinc and fruit acid (alpha-hydroxy acid) for acne.

Zinc for the common cold

Role of Zinc in Immune System and Anti-Cancer Defense Mechanisms

Interactions of iron with manganese, zinc, chromium, and selenium as related to prophylaxis and treatment of iron deficiency.

Excessive intake of zinc impairs immune responses

The Bradford Hill criteria and zinc-induced anosmia: a causality analysis

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Clinical, immunological, anti-inflammatory and antioxidant roles of zinc

Zinc decreases C-reactive protein, lipid peroxidation, and inflammatory cytokines in elderly subjects: a potential implication of zinc as an atheroprotective agent

Recommended Dietary Allowances: 10th Edition

Zinc and immunity: An essential interrelation

Diet and Nutritional Factors in Male (In)fertility-Underestimated Factors

Zinc effects on NMDA receptor gating kinetics

Glutamate and depression: Reflecting a deepening knowledge of the gut and brain effects of a ubiquitous molecule

Effect of Zinc Supplementation on Physical and Psychological Symptoms, Biomarkers of Inflammation, Oxidative Stress, and Brain-Derived Neurotrophic Factor in Young Women with Premenstrual Syndrome: a Randomized, Double-Blind, Placebo-Controlled Trial

Zinc monotherapy increases serum brain-derived neurotrophic factor (BDNF) levels and decreases depressive symptoms in overweight or obese subjects: A double-blind, randomized, placebo-controlled trial

Effects of pyridoxine on dreaming: a preliminary study

A synergistic effect of a daily supplement for 1 month of 200 mg magnesium plus 50 mg vitamin B6 for the relief of anxiety-related premenstrual symptoms: a randomized, double-blind, crossover study

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Zinc Deficiency

Estimating the global prevalence of zinc deficiency: results based on zinc availability in national food supplies and the prevalence of stunting

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Zinc deficiency in low- and middle-income countries: prevalence and approaches for mitigation.

Prevalence of Zinc Deficiency in Healthy 1-3-Year-Old Children from Three Western European Countries.

ISSN exercise & sports nutrition review update: research & recommendations

Effects of a Novel Zinc-Magnesium Formulation on Hormones and Strength

Effects of Zinc Magnesium Aspartate (ZMA) Supplementation on Training Adaptations and Markers of Anabolism and Catabolism

Serum testosterone and urinary excretion of steroid hormone metabolites after administration of a high-dose zinc supplement

Zinc is an essential trace element for spermatogenesis.

Moderate zinc deficiency reduces testicular Zip6 and Zip10 abundance and impairs spermatogenesis in mice.

Relationship between abnormal sperm morphology induced by dietary zinc deficiency and lipid composition in testes of growing rats.

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Effects of dietary zinc depletion on seminal volume and zinc loss, serum testosterone concentrations, and sperm morphology in young men

Association between seminal plasma zinc level and asthenozoospermia: a meta-analysis study

Zinc levels in seminal plasma and their correlation with male infertility: A systematic review and meta-analysis

Effect of zinc administration on plasma testosterone, dihydrotestosterone, and sperm count

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Effectiveness of Pharmacological Intervention Among Men with Infertility: A Systematic Review and Network Meta-Analysis.

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Relationship of serum copper and zinc levels to HIV-1 seropositivity and progression to AIDS

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Benefit of oral zinc supplementation as an adjunct to zidovudine (AZT) therapy against opportunistic infections in AIDS.

Efficacy and safety of zinc supplementation for adults, children and pregnant women with HIV infection: systematic review.

Zinc inhibits nonheme iron bioavailability in humans

New insights about iron bioavailability inhibition by zinc

Adverse Effects of Excessive Zinc Intake in Infants and Children Aged 0-3 Years: A Systematic Review and Meta-Analysis

Supplemental zinc lowers measures of iron status in young women with low iron reserves

Competitive inhibition of iron absorption by manganese and zinc in humans.

Effect of increasing concentrations of zinc on the absorption of iron from iron-fortified milk

Acute inhibition of iron bioavailability by zinc: studies in humans

Iron and Zinc Homeostasis and Interactions: Does Enteric Zinc Excretion Cross-Talk with Intestinal Iron Absorption?

Interactive effects of iron and zinc on biochemical and functional outcomes in supplementation trials.

The relationship between libido and testosterone levels in aging men

Low total testosterone levels are associated with the metabolic syndrome in elderly men: the role of body weight, lipids, insulin resistance, and inflammation; the Ikaria study

High Rates of Depression and Depressive Symptoms among Men Referred for Borderline Testosterone Levels

Salivary testosterone: associations with depression, anxiety disorders, and antidepressant use in a large cohort study

Age trends in the level of serum testosterone and other hormones in middle-aged men: longitudinal results from the Massachusetts male aging study

Hypothalamic-pituitary-testicular axis disruptions in older men are differentially linked to age and modifiable risk factors: the European Male Aging Study

Age-specific population centiles for androgen status in men

Sleep deprivation lowers reactive aggression and testosterone in men

Effect of 1 week of sleep restriction on testosterone levels in young healthy men

Association between sleep and morning testosterone levels in older men

Sleep deprivation and adaptive hormonal responses of healthy men

Sleep deprivation reduces circulating androgens in healthy men

Insufficient sleep undermines dietary efforts to reduce adiposity

Acute and chronic effects of resistance exercise on the testosterone and cortisol responses in obese males: a systematic review

Hormonal responses and adaptations to resistance exercise and training

Relationship between stress hormones and testosterone with prolonged endurance exercise

Chronic Low Testosterone Levels in Endurance Trained Men: The Exercise- Hypogonadal Male Condition

Low testosterone in men with type 2 diabetes: significance and treatment

Characteristics of secondary, primary, and compensated hypogonadism in aging men: evidence from the European Male Ageing Study

Correlates of low testosterone and symptomatic androgen deficiency in a population-based sample

A Perspective on Middle-Aged and Older Men With Functional Hypogonadism: Focus on Holistic Management

Body weight loss reverts obesity-associated hypogonadotropic hypogonadism: a systematic review and meta-analysis

Age-associated changes in hypothalamic-pituitary-testicular function in middle-aged and older men are modified by weight change and lifestyle factors: longitudinal results from the European Male Ageing Study

Effect of vitamin D supplementation on testosterone levels in men

Association of vitamin D status with serum androgen levels in men

Dietary Reference Intakes for Calcium and Vitamin D

Letter to Veugelers, P.J. and Ekwaru, J.P., A statistical error in the estimation of the recommended dietary allowance for vitamin D. Nutrients 2014, 6, 4472-4475; doi:10.3390/nu6104472

A statistical error in the estimation of the recommended dietary allowance for vitamin D

Correlation between serum testosterone level and concentrations of copper and zinc in hair tissue

Zinc

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